Corrugated cardboard boxes have been designed with a variety of sizes, shapes and in a variety of multicolor printings these days, and in coping with such designs, there have been presented a variety of functions of the machine for manufacturing the corrugated cardboard boxes, accordingly. Now, referring to the conventional construction of the corrugated cardboard box manufacturing machine with reference to FIGS. 1 through 4, there are shown provided a blank board supply station 1, a first printing machine 2, a second printing machine 3, printing cylinders 4, a transfer conveyor 5, a rotary die cutting station 6, a anvil cylinder 7, a die-cut cylinder 8, a die element 9, a board delivery conveyor (a scrap conveyor; a conveyor for a planar object) 10, a sheet of corrugated board 11, a die board 11' (through the single-cutting process), a died board 11" (through the double-cutting process), a stacker-conveyor 12, a counter-stacker 13, a board stopper 14, a spacing 16, a lifter 17, and a counting photoelectric tube 18, wherein a sheet of corrugated cardboard 11 is fed for printing by the board supply station 1 with such a rate of delivery of a sheet per single rotation of the printing cylinders 4 in the printing machines 2, 3, thereafter is delivered outwardly by the transfer conveyor 5 for having the printing ink put in the surface of a cardboard 11 dried up, and then is died to a shape of cardboard box by way of the rotary die cutter 6. The die element 9 comprises a cutting knife edge or the like implanted around the circumferential surface of a curved veneer board of a specified thickness, which is to be mounted onto the die-cut cylinder 8 by using bolts, and is adapted to cut and die a sheet of cardboard 11 to be fed from the foregoing step into the nip with the anvil cylinder 7, which is wrapped with a layer of urethane rubber or the like for making the cutting easier and preventing the wear of cutting edge, with a predetermined timing of cuting and dieing. The delivery conveyor (scrap conveyor) 10 is formed by a plurality of such carrier members as V-shaped belts or ropes having a circular section in an attempt to promote the dropping of chippings and cuttings from the product at the area where there is provided a specific means such as an air blower or a vibrator, and is constructed in a duplex structure for carrying the died board 11' in a sandwiched relationship over to a stacker-conveyor 12. There is provided a suction equipment in the stacker-conveyor 12, which is adapted to attract by sucking and deliver the died cardboard 11' at a slow speed in the attempt to reduce a impace shock of the board against the cardboard stopper 14 provided in the counter-stacker 13 when hit, thus obviating a possibility of damages and/or irregular stacking of the cardboards from occurring when stacked upon the lifter 17. Also, the cardboard stopper 14 is designed shiftable back and forth by way of a hydraulic cylinder or the like in accordance with a given width of the died board 11' as schematically shown in FIGS. 1 and 2.
The cardboard box manufacturing machine is of the type that a sheet of cardboard 11 may be set either for one-piece cutting or for longitudinal double-piece cutting according to the size of a box to be died by using the die element 9 of the rotary die cutter 6. FIG. 3(III) shows the case of the single-piece cutting process, FIG. 4(III) shows the longitudinal double-piece cutting, and FIG. 4(IV) shows the four-piece cutting process (double-cuttings in the transversal and longitudinal ways making four pieces of boards), respectively. The die element 9 is to be set in the circumferential surface of the die cut cylinder 8, with a single-piece or double-piece cutting knife element implanted in working position in accordance with the size of a product box to be manufactured, and with a spacing 16. This spacing 16 is provided for the reduction of conveying speed in consideration of a too great shock to be given to the died cardboard 11' when hit against the cardboard stopper 14, which is taken in the following manner; when a series of died cardboards 11' after being died by the die cut cylinder 8 are stacked upon the lifter 17 by using the stacker-conveyor 12, as the carrying speed of the stacker-conveyor 12 will, when the single-piece cutting is conducted (FIG. 3(III)), bring a too large shock on the died sheet 11' when hit against the cardboard stopper 14, if V.sub.1 .div.V.sub.2 (the circumferential speed of the die cut cylinder 8 and the carrying speed of the delivery conveyor 10 are V.sub.2, and the carrying speed of the stacker-conveyor 12 is V.sub.1, as shown in FIG. 3(I)), the speed V.sub.1 of the stacker-conveyor 12 is then reduced by using the spacing 16 as shown in FIG. 3(II) to: ##EQU1## However, in the case of the double-piece cutting process (FIG. 4(III)), when the carrying speed V.sub.1 of the stacker-conveyor 12 is reduced down to V.sub.1 =V.sub.2 .times.l/L as shown in FIG. 4(II), since the sheet 11" die for the double-cutting process is cut to the shape in which the foregoing piece and the following piece are left connected with each other by the die cutter, it would not be feasible to have normal cutting operation as these died sheets 11" may come to overlap one upon the other, and consequently, the carrying speed V.sub.1 of the stacker-conveyor 12 is forcibly made V.sub.1 .div.V.sub.2 as shown in FIG. 4(I) (identical with FIG. 3(I)), then resulting in such undesirable problems that the leading edges of the died sheet 11" would be damaged by a too large shock load when hit against the cardboard stopper 14 in stacking, or the died sheets 11" would be stacked irregularly.